Expert Panel on Detection, Evaluation, and Treatment of High Blood
Cholesterol in Adults. Executive summary of the Third Report of the National Cholesterol Education
Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High
Blood Cholesterol in Adults (Adult Treatment Panel III). JAMA.2001;285:2486-2497.PubMed

Expert Panel on Detection, Evaluation, and Treatment of High Blood
Cholesterol in Adults. Summary of the second report of the National Cholesterol Education
Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High
Blood Cholesterol in Adults (Adult Treatment Panel II). JAMA.1993;269:3015-3023.PubMed

Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol
in plasma, without use of the preparative ultracentrifuge. Clin Chem.1972;18:499-502.PubMed

Context To enhance the effectiveness of diet in lowering cholesterol, recommendations
of the Adult Treatment Panel III of the National Cholesterol Education Program
emphasize diets low in saturated fat together with plant sterols and viscous
fibers, and the American Heart Association supports the use of soy protein
and nuts.

Objective To determine whether a diet containing all of these recommended food
components leads to cholesterol reduction comparable with that of 3-hydroxy-3-methylglutaryl
coenzyme A reductase inhibitors (statins).

Design Randomized controlled trial conducted between October and December 2002.

Setting and Participants Forty-six healthy, hyperlipidemic adults (25 men and 21 postmenopausal
women) with a mean (SE) age of 59 (1) years and body mass index of 27.6 (0.5),
recruited from a Canadian hospital-affiliated nutrition research center and
the community.

Results The control, statin, and dietary portfolio groups had mean (SE) decreases
in low-density lipoprotein cholesterol of 8.0% (2.1%) (P = .002), 30.9% (3.6%) (P<.001), and 28.6%
(3.2%) (P<.001), respectively. Respective reductions
in C-reactive protein were 10.0% (8.6%) (P = .27),
33.3% (8.3%) (P = .002), and 28.2% (10.8%) (P = .02). The significant reductions in the statin and
dietary portfolio groups were all significantly different from changes in
the control group. There were no significant differences in efficacy between
the statin and dietary portfolio treatments.

Conclusion In this study, diversifying cholesterol-lowering components in the same
dietary portfolio increased the effectiveness of diet as a treatment of hypercholesterolemia.

Most dietary manipulations result in modest cholesterol reductions of
4% to 13%,1- 10 and
diet has been considered by some as a relatively ineffective therapy.11 In contrast, 3-hydroxy-3-methylglutaryl coenzyme
A reductase inhibitors (statins) repeatedly have been shown to reduce mean
serum low-density lipoprotein cholesterol (LDL-C) concentrations by 28% to
35% in long-term trials,12- 14 with
corresponding reductions in cardiovascular death of 23% to 32% in both primary
and secondary prevention trials.13,14 Recently,
to boost effectiveness of diet for primary prevention of cardiovascular disease,
the Adult Treatment Panel (ATP III) of the National Cholesterol Education
Program has recommended addition of plant sterols (2 g/d) and viscous fibers
(10-25 g/d) to the diet.15 The American Heart
Association has also drawn attention to the possible benefits of soy proteins
and the potential value of nuts.16 In turn,
the US Food and Drug Administration now permits health claims for coronary
heart disease (CHD) risk reduction, based on cholesterol lowering, for foods
delivering adequate amounts of plant sterols,17 viscous
fibers (oat β-glucan and psyllium),18,19 and
soy protein,20 and a health claim for nuts
is being considered. Despite the large potential for cholesterol reduction,
this dietary combination has never been compared directly with a statin. To
assess the effectiveness of this dietary portfolio approach, we therefore
studied a group of hyperlipidemic adults who were randomized to 1 of 3 treatments:
the combination dietary portfolio, a diet lacking the additional active dietary
ingredients but with a similar very low-saturated-fat content (control), or
the same low-saturated-fat diet with addition of a statin.

Methods

Participants

Fifty-five participants were recruited from hyperlipidemic patients
attending the Clinical Nutrition and Risk Factor Modification Center at St
Michael's Hospital, Toronto, Ontario, and from newspaper advertisements. Postmenopausal
women were recruited because of the increase in LDL-C and CHD risk in women
in this age group and to avoid possible fluctuations in blood lipids related
to the menstrual cycle. All participants were reluctant to take statins and
wished to determine the relative effectiveness of diet. Four participants
who were randomized did not start the study. Additionally, 3 withdrew during
the first study week because of family ill health, job relocation, or time
commitment required by the metabolic diet, and 2 were withdrawn because of
either a transient elevation of liver enzymes or symptoms of muscle discomfort
(Figure 1). Forty-six healthy, hyperlipidemic participants completed the
study (25 men and 21 postmenopausal women); the mean (SE) age was 59 (1) years
(range, 36-85 years) and mean (SE) body mass index (calculated as weight in
kilograms divided by the square of height in meters) was 27.6 (0.5) (range,
20.5-35.5) (Table 1). All participants
had previously high LDL-C levels (>158 mg/dL [>4.1 mmol/L]).15 No
participants had a history of cardiovascular disease, untreated hypertension
(blood pressure >140/90 mm Hg), diabetes, or renal or liver disease, and none
were taking medications known to influence serum lipids apart from 3 women
who were taking stable doses of thyroxine, 1 of whom was also taking estrogen
therapy. Twenty-one participants had started statins and had discontinued
them at least 2 weeks prior to the study (9 control participants, 7 dietary
portfolio participants, and 5 statin participants). Five participants were
taking antihypertensive medications at a constant dose prior to and during
the study. The majority (n = 26) were taking vitamin preparations. Other,
more commonly used nonprescription drugs and supplements taken throughout
the study period included aspirin and anti-inflammatory drugs (n = 5), calcium
(n = 8), glucosamine (n = 3), grapeseed oil (n = 2), saw palmetto (n = 2),
garlic (n = 2), and magnesium (n = 2).

Study Protocol

The study followed a randomized parallel design and was carried out
between October and December 2002. Participants followed their own low-saturated-fat
therapeutic diets for 1 month prior to the start of the study. They were then
stratified based on sex and pretreatment LDL-C level and were randomized to
a very low-saturated-fat dairy and whole-grain cereal diet either with or
without a statin or a diet containing viscous fibers, plant sterols, soy foods,
and almonds. Each treatment lasted for 1 month. All foods were provided except
for fresh fruits and vegetables. Body weight was measured weekly and blood
samples were obtained after 12-hour overnight fasts at 2-week intervals. On
each clinic visit, blood pressure was measured twice in the nondominant arm
using a mercury sphygmomanometer by the same observer. Seven-day diet histories
were obtained for the week prior to the 1-month treatment period. Completed
menu checklists were returned at weekly intervals during the 4-week diet period
and checked by the dietitians, who also recorded the participants' previous
week's exercise and ensured that it was constant over the course of the study
period.

At weekly intervals, participants recorded their overall feeling of
satiety using a 9-point bipolar semantic scale in which −4 was excessively
hungry, 0 was neutral, and +4 was discomfort due to excess food intake.

Participants were randomized by the statistician using a random number
generator and SAS version 6.12 software (SAS Institute Inc, Cary, NC) in a
separate location from the clinic. The statistician held the code for the
placebo and statin tablets provided with the control and statin diets, respectively.
This aspect of the study was therefore double-blind. The dietitians were not
blinded to the diet because they were responsible for patients' diets and
for checking diet records. The laboratory staff responsible for analyses were
blinded to treatment and received samples labeled with name codes and dates.

The study was approved by the ethics committees of the University of
Toronto and St Michael's Hospital. Written informed consent was obtained from
all participants.

Diets

The diets eaten before the 4-week study were the participants' routine
therapeutic low-fat diets, which were similar to current National Cholesterol
Education Program guidelines (<7% energy from saturated fat and <200
mg/d of dietary cholesterol)15 and previously
referred to as a Step II diet21 (Table 2).

During the 4-week study period, weight-maintaining diets were provided
based on estimated caloric requirements using foods available in supermarkets
and health food stores. All diets were vegetarian. The aim of the dietary
portfolio was to provide 1.0 g of plant sterols per 1000 kcal of diet in a
plant sterol ester–enriched margarine; 9.8 g of viscous fibers per 1000
kcal of diet from oats, barley, and psyllium; 21.4 g of soy protein per 1000
kcal as soy milk and soy meat analogs; and 14 g of whole almonds per 1000
kcal of diet. Emphasis was placed on eggplant and okra as additional sources
of viscous fiber (0.2 g/1000 kcal and 0.4 g/1000 kcal, respectively). Thus,
200 g of eggplant and 100 g of okra were prescribed to be eaten as part of
a 2000-kcal diet on alternate days. Eggs (1/wk) and butter (9 g/d) were also
provided in the dietary portfolio to balance the saturated fat and dietary
cholesterol in the control diet. This dietary portfolio has been described
in detail previously.22

The control diet used skim milk, fat-free cheese and yogurt, and egg
substitute and liquid egg white to achieve low intake of saturated fat. High
fiber intake was obtained by use of whole-grain breakfast cereals (fiber,
2.5 g/1000 kcal of diet) and bread (fiber, 2.0 g/1000 kcal of diet) made from
100% whole-wheat flour and wheat bran added to a high-dairy-protein muffin
(fiber, 7.3 g/1000 kcal of diet). This diet therefore lacked sources of viscous
fibers, plant sterols, and almonds. Skim-milk products replaced the soy and
vegetable protein foods consumed as part of the dietary portfolio, and high
monounsaturated sunflower oil (9 g/1000 kcal) and safflower oil (5 g/1000
kcal) were incorporated into the control diet (eg, muffins) to balance the
fatty acid profile of the dietary portfolio. The macronutrient profile of
the diets recorded as consumed in week 4 is shown in Table 3. Typical 1-day menus for the control diet and dietary portfolio
are shown in Table 4.

Participants were provided with self-taring electronic scales (Salter
Housewares, Kent, England) and asked to weigh all food items consumed prior
to and during the study period. During the study period, all foods to be consumed
by participants were provided initially by courier and then at weekly clinic
visits, with the exception of fruit and low-calorie, non–starch-containing
vegetables. Okra was the exception and was provided in the dietary portfolio.
Participants were instructed to obtain specific fruits and vegetables from
their local stores and were reimbursed on presentation of receipts. Participants
were provided with a 7-day rotating menu plan on which they checked off each
item as eaten and confirmed the weight of the foods. The same menu plan was
used for all participants but was modified to suit individual preferences,
provided that the goals for viscous fiber, soy protein, plant sterol, and
almond consumption were met. Noncaloric beverages were not restricted.

Food use was made as straightforward as possible so that commercial
dishes were ready for microwave or oven cooking, packs of instant soups were
provided to be reconstituted with boiling water, and, when possible, meal
portions were prescribed in multiples of whole units (eg, 1 cup of instant
soup, 1 frozen dinner, 2 soy hot dogs, or 4 soy deli slices). Diet foods were
packed in a designated central location and shipped by courier in separate
boxes for dry, refrigerated, and frozen goods. Egg substitutes and soy and
dairy foods were shipped in their commercial packages to be refrigerated on
receipt by the participants.

Compliance was assessed from the completed weekly checklists and from
the return of uneaten food items.

Statin Therapy

Twenty-milligram lovastatin tablets (Genpharm Inc, Etobicoke, Ontario)
were crushed and delivered in Vegiecap capsules (Capsugel, Morris Plains,
NJ). Identical placebo capsules containing lactose and blue food coloring
were also prepared (Pharmacy.ca [http://www.pharmacy.ca/home.shtml],
Toronto, Ontario). Both lovastatin and placebo
capsules were dispensed by the hospital pharmacy in identical containers marked
with the participant's name according to the randomization determined by the
statistician. Participants were asked to take 1 capsule (20 mg of lovastatin
or placebo) per day in the evening for the 28 days of the study and to return
the containers for capsule counts at the end of the month.

Analyses

All samples from a given individual were labeled by code and analyzed
in the same batch. Serum was analyzed according to the Lipid Research Clinics
protocol23 for total cholesterol, triglycerides,
and high-density lipoprotein cholesterol (HDL-C) after dextran sulphate–magnesium
chloride precipitation.24 Low-density lipoprotein
cholesterol was calculated.25 Serum apolipoprotein
A1 and B were measured by nephelometry (intra-assay coefficient of variation,
2.2% and 1.9%, respectively).26 Serum samples,
stored at −70°C, were analyzed for C-reactive protein by end-point
nephelometry (coefficient of variation, 3.5%) (Behring BN-100, N high-sensitivity
C-reactive protein reagent, Dade-Behring, Mississauga, Ontario).

Diets were analyzed using a program based on US Department of Agriculture
data and developed in our laboratory to allow addition of data on foods relevant
to ongoing studies after analysis in the laboratory for protein, total fat,
and dietary fiber using American Organization of Analytical Chemists methods
and fatty acids by gas chromatography.22 More
than half of the foods used in the diets had been analyzed in the laboratory.

Statistical Analysis

Results were calculated as mean (SE). The mean differences in blood
lipid values between week 2 and week 4 were not greater than 9.3 mg/dL (≤0.24
mmol/L) (range, −7.7 to 9.3 mg/dL [−0.20 to 0.24 mmol/L]) and
the week 4 level was therefore used throughout for all analyses as the end-point
value. The significance of the differences between treatments was assessed
by the Student-Neuman-Keuls multiple range test (SAS PROC GLM).27 The
analysis of covariance model used the change from week 0 to week 4 as the
response variable and treatment and sex by treatment interaction as main effects,
with baseline as covariate. Response variables were normally distributed,
with the exception of C-reactive protein and the ratio of apolipoprotein B
to apolipoprotein A1 in the dietary portfolio group, triglycerides in the
statin group, and body mass index in the control group. An intention-to-treat
analysis was also carried out by including the 5 participants for whom baseline
samples were available but who dropped out or were withdrawn prior to the
week 2 blood sample. Three assumptions were assessed: that these participants
would show no change, 50% of the mean change, or 100% of the mean change observed
for that treatment. A 2-tailed paired t test was
used to assess the significance of the percentage change from baseline. With
15 participants per treatment group, and assuming a 10% SD of effect with α
= .05 and β = .80, we had sufficient power to detect an 8% change in
LDL-C across treatments as significant. The CHD risk equations were used as
described by Anderson et al.28 Ten-year CHD
risk was calculated, including in the model age, sex, systolic blood pressure,
total cholesterol and HDL-C, smoking, diabetes, and definite electrocardiographic
evidence of left ventricular hypertrophy.28 Only
1 participant smoked and did so consistently throughout the study, and none
had diabetes or evidence of left ventricular hypertrophy.

Results

For the majority of participants, compliance was good as assessed from
completed metabolic diet checklists and return of uneaten food items. When
expressed as the percentage of prescribed calories recorded as eaten during
week 4, compliance was 93% (3%) for control, 95% (3%) for statin, and 94%
(3%) for the dietary portfolio. Similarly, 98% of capsules provided were taken.
All participants believed they were eating as much food as they were capable
of without experiencing discomfort (satiety rating, <3.0) at week 4 (control,
2.3 [0.4]; statin, 2.4 [0.3]; and dietary portfolio, 2.8 [0.2]). Participants
lost a similar amount of weight in all 3 treatments (control, 0.3 [0.2] kg; P = .22; statin, 0.2 [0.1] kg; P =
.15; dietary portfolio, 0.4 [0.2] kg; P = .06).

Blood Lipids and C-Reactive Protein

No differences were observed among the 3 treatment groups in baseline
blood measurements. In the control group, percentage changes from baseline
to week 4 were as follows: LDL-C, −8.0% (2.1%) (P = .002); LDL-C–HDL-C ratio, +3.0% (2.8%) (P = .31); and C-reactive protein, −10.0% (8.6%) (P = .27). In the statin and dietary portfolio groups, the respective
data were as follows: LDL-C, −30.9% (3.6%) (P<.001)
and −28.6% (3.2%) (P<.001); LDL-C–HDL-C
ratio, −28.4% (4.2%) (P<.001) and −23.5%
(3.2%) (P<.001); and C-reactive protein, −33.3%
(8.3%) (P = .002) and −28.2% (10.8%) (P = .02), with no differences between week 2 and week 4
values (Figure 2). The reductions
in blood lipids in both the dietary portfolio and statin groups were significantly
greater (P<.005) than the respective changes in
the control group for total cholesterol, LDL-C, apolipoprotein B, and the
ratios of total cholesterol to HDL-C, LDL-C to HDL-C, and apolipoprotein B
to apolipoprotein A1, with no significant differences between the dietary
portfolio and statin groups (Table 5).
No differences in response were observed between sexes. In both the dietary
portfolio and statin groups, C-reactive protein was reduced significantly
more than in the control group (P<.005), but again,
no difference was observed between the dietary portfolio and statin groups.

In the dietary portfolio and statin groups, the calculated CHD risk
was reduced similarly (24.9% [5.5%]; P<.001 and
25.8% [4.4%]; P<.001, respectively). These reductions
were also significantly different from the reduction (3.0% [5.2%]; P = .57) in the control group (P<.005)
(Table 5). The risk reductions
were largely due to the reductions in blood lipids. When blood pressure was
held constant at 120 mm Hg in the risk equations, the blood lipid changes
accounted for 70% and 82% of the risk reduction in the dietary portfolio and
statin groups, respectively.

Intention-to-Treat Analysis

This study was also analyzed on the basis of intention to treat, including
the 5 individuals with baseline values who dropped out or were withdrawn during
the first and second weeks (before the week 2 and week 4 samples were taken
for determination of blood lipids). (The 4 randomized participants for whom
no baseline samples were obtained could not be included in this analysis.)
Irrespective of whether it was assumed that the additional participants would
have shown no response or 50% or 100% of the observed mean response, the same
differences in blood lipid levels were preserved as significantly different
among the treatment groups, as observed when these participants were not included
in the analysis. Furthermore, the mean reductions across treatments in LDL-C
were still significant at −7.5% (2.0%) (P =
.002) for control; −28.6% (3.2%) (P<.001)
for dietary portfolio; and −24.0% (4.2%) (P<.001)
for statin when it was assumed that the 5 additional participants showed no
change in response to the treatments. Only for C-reactive protein and CHD
risk was the significance level reduced (from P<.005
to P<.05) for the differences between control
and both dietary portfolio and statin treatments.

Comment

These data confirm that use of a particular formulation of more recent
general recommendations (ATP III, American Heart Association)15,16 can
greatly enhance the cholesterol-lowering effect of diet. The reductions in
blood lipids were not significantly smaller than those achieved with the initial
dose of lovastatin, the first-generation statin marketed for cholesterol reduction.

The dietary components used in our portfolio are all well recognized
for their cholesterol-lowering properties.1,16- 20 Meta-analyses
have indicated reductions in serum LDL-C of 6% to 7% for 9 to 10 g/d of psyllium,3 with smaller reductions for other viscous fibers29; 13% for 1 to 2 g/d of plant sterols4;
12.5% for 45 g/d of soy protein2; and 1% for
10 g/d of almonds.1 Lower intakes of saturated
fat may lead to smaller reductions in cholesterol for soy protein,5 and the same may be true for other interventions,
including plant sterols.30 A reduction in LDL-C
of 4% to 7% may therefore be more appropriate for each component when taken
with very low-saturated-fat diets and account for the decrease in LDL-C of
28% observed in this dietary portfolio. In this study, the fatty acid and
cholesterol intakes were both low and similar in the dietary portfolio and
control groups. The benefits on blood lipids of higher monounsaturated fat
intake associated with nut consumption, though not expected in the present
study because of the balanced fatty acid profiles of the diets,31,32 would
be expected under conditions of monounsaturated fatty acid substitution.31- 34

The lower saturated fatty acid intakes made possible by the nature of
the foods selected for the dietary portfolio may be a further advantage. Despite
the relatively low saturated fatty acid and cholesterol content of the prestudy
diets, application of the Hegsted equation35 suggested
that the differences in fatty acid and cholesterol intakes between the prestudy
and study diets could account for 88%, 25%, and 27%, respectively, of the
reductions observed in serum cholesterol in the control, statin, and dietary
portfolio groups.

The different modes of action of the components on the dietary portfolio
may have contributed to the additive effect. Viscous fibers increase bile
acid losses,29 plant sterols reduce cholesterol
absorption,7 and soy proteins reduce hepatic
cholesterol synthesis and increase LDL receptor messenger RNA and so potentially
increase uptake of cholesterol.8,9 Almonds
contain a monounsaturated fatty acid– and plant sterol–rich oil
that has been shown to lower LDL-C34 together
with vegetable proteins, fiber, and other phytochemicals, which are likely
to operate through a range of mechanisms.10

Another feature of interest relating to the dietary portfolio was its
ability to reduce C-reactive protein concentrations. This function, also observed
with statins, has been related to their direct anti-inflammatory effect36 and has been considered possibly responsible for
some of the reduction in CHD observed with statin use, best demonstrated in
women with normal LDL-C levels.37 C-reactive
protein reductions have not previously been reported with conventional cholesterol-lowering
diets. It is therefore possible that lower C-reactive protein concentrations
are a general consequence of effective cholesterol reduction, but in the present
study, in common with other studies, C-reactive protein change was not significantly
related to the change in LDL-C (r = 0.20; n = 46; P = .17).37,38 Also,
in the present study, caution must be taken specifically in interpreting the
C-reactive protein findings because of the substantial but nonsignificant
differences between treatment baseline values and, more generally, because
no intervention studies exist specifically to test the effect of C-reactive
protein reduction on CHD risk.

The data currently available from clinical trials demonstrating reductions
in cardiovascular disease risk support an important role for dietary change,
which includes increased intakes of fiber, vegetable oils, and proteins from
soy and other legumes, nuts, fruits, and vegetables.39- 41 Furthermore,
in large cohort studies, high fiber intakes have consistently been associated
with reduction in CHD risk39 and CHD risk factors42; more recently, so has increased nut consumption.43- 45 In this respect,
the recent dietary recommendations (ATP III, American Heart Association, US
Food and Drug Administration) may further increase the effectiveness of diet
in reducing the risk of cardiovascular disease. In the future, other plant
food components with specific mechanisms of action may be added to this portfolio.46- 48

Despite the effectiveness and safety of statins, there are still some
individuals for whom physicians are reluctant to prescribe statins because
of elevations of muscle or liver enzymes.49 There
are also those who would prefer to control their blood lipid levels by nonpharmacological
means, particularly in view of recent, less satisfactory outcomes with statin
use in older people.50,51 For
such individuals, the dietary portfolio approach might provide a therapeutic
option.

From our participants' perspective, of the 36 (78%) who completed the
study and provided formal comments, 40% found the dietary portfolio acceptable
with little further modification; however, an equal number thought that a
greater variety of foods was required, 27% thought that the food volume was
too great, and 13% required meat as part of their meals. The 5 most popular
foods were almonds, ground soy (simulated ground beef), oat bran cereal, oat
bran bread, and plant sterol margarine.

In conclusion, current dietary recommendations15 focusing
on diets low in saturated fat have been expanded to include foods high in
viscous fibers (eg, oats and barley) and plant sterols. These guidelines,
together with additional suggestions to include vegetable protein foods (soy)16 and nuts (almonds), appear to reduce LDL-C levels
similarly to the initial therapeutic dose of a first-generation statin. However,
before the true effectiveness of this dietary change can be assessed, studies
must be undertaken in patients who assemble the diets for themselves on a
routine basis. Using the experience gained, further development of this approach
may provide a potentially valuable dietary option for cardiovascular disease
risk reduction in primary prevention.

Expert Panel on Detection, Evaluation, and Treatment of High Blood
Cholesterol in Adults. Executive summary of the Third Report of the National Cholesterol Education
Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High
Blood Cholesterol in Adults (Adult Treatment Panel III). JAMA.2001;285:2486-2497.PubMed

Expert Panel on Detection, Evaluation, and Treatment of High Blood
Cholesterol in Adults. Summary of the second report of the National Cholesterol Education
Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High
Blood Cholesterol in Adults (Adult Treatment Panel II). JAMA.1993;269:3015-3023.PubMed

Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol
in plasma, without use of the preparative ultracentrifuge. Clin Chem.1972;18:499-502.PubMed